Changeable-pitch propeller



United States Patent 3,354,965 CHANGEABLE-PITCH PROPELLER Fritz Reimers, Bridge St., Mont Clare, Pa. 19453 Filed May 15, 1967, Ser. No. 638,502 4 Claims. (Cl. 170160.29)

ABSTRACT OF THE DISCLOSURE This invention is essentially concerned with a changeable-pitch propeller having positive pitch-changing action upon reversal of the driven direction.

Background of the invention The instant application is related to subject matter similar to that of my prior United States Patent No. 3,294,176, constituting an improvement thereover.

Summary It is an important object of the present invention to provide a changeable-pitch propeller construction, wherein change or reversal of pitch is automatically and positively actuated upon reversal of the propeller drive.

It is another object of the present invention to provide a changeable-pitch propeller of the type described, which may be employed in marine or air vehicles, or otherwise where changeable-pitch propellers may be utilized, and which is extremely simple in construction and durable and entirely reliable throughout a long useful life.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims.

Brief description of the drawing FIGURE 1 is a sectional view illustrating an assembled changeable-pitch propeller construction in accordance with the teachings of the present invention.

FIGURE 2 is a sectional view taken generally along the line 22 of FIGURE 1, illustrating propeller-blade rotation in one direction.

FIGURE 2a is a view similar to FIGURE 2, but illustrating propeller rotation in the other direction.

FIGURE 3 is a transverse sectional view taken generally along the line 3-3 of FIGURE 1, illustrating operating means of the present invention in a neutral condition of the propeller drive.

FIGURE 4 is a sectional view similar to FIGURE 3, but illustrating the operating and control means in a reverse condition of drive, and showing in phantom the forward condition of drive.

Description of the preferred embodiment Referring now more particularly to the drawings, and specifically to FIGURE 1 thereof, a propeller assembly is there generally designated 10, and illustrated as being mounted in a support structure 11 having a journal hearing 12.

More particularly, the propeller assembly 10 includes an elongate, hollow outer shaft 15 extendin through the support structure 11 and rotatably journaled in the bearing 12. The forward or outer end of the hollow outer shaft 15 may be enlarged, as at 16, rightward of the mounting structure 11 as seen in FIGURE 1.

Extending coaxially through the outer shaft 15 is a bore 18, which opens through-opposite ends of the shaft and defines in internal hollow therethrough. The enlarged outer-end portion 16 of shaft 15 may be provided with a plurality of radially extending thru openings or holes 20, each opening at its radially inner end into the hollow or bore 18 of the outer shaft 15. While a pair of radially extending openings 20 are shown in the illustrated embodiment, it is appreciated that a greater number may be provided, if desired.

An inner shaft 21 extends coaxially through the outer shaft 15, being rotatably journaled in the bore 18 of the outer shaft. The inner shaft 21 may have its opposite ends projecting beyond opposite ends of the outer shaft 15, the inner end of inner shaft 21 being adapted for coupling, as at 22, to a reversible drive source, as by a reversible drive shaft 23. The forward or outer end of inner shaft 21 may project beyond the forward-end enlargement 16 of shaft 15, and may there be provided with a fairing cap or retainer head 24 having its external surface configured for smooth surface mergence with the external surface of outer-shaft enlargement 16.

Spaced between the ends of inner shaft 21, the inner shaft may be provided with a circumferential recess 01' groove 25. The recess or groove 25 may be formed, at least at one end thereof, with a circumferentially castellated or toothed formation, say to define teeth 26. In the illustrated embodiment, the teeth 26 are formed at the rear end of circumferential recess 25 extending forwardly int-o the recess and arranged in circumferentially spaced relation about the inner shaft 21. The teeth 26 may assume the configuration of raised bosses or lands on the recess 25 having an external diameter substantially equal to that of the shaft 21, as illustrated As best seen in FIGURE 1, the circumferential groove 25 is located in facing relation with the openings 20 of the outer shaft 15, and the groove may be of a length longitudinally of the inner shaft approximately equal to the diameter of each opening 20, for substantial registry therewith.

Projecting radially outwardly from the enlarged end portion 16 of outer shaft 15 may be a pair of propeller blades 28. Associated with each blade 28, at the inner end thereof, is a shank 29 extending radially inward through a respective outer-shaft opening 20 and journaled therein for rotation about the axis of the respective shank. That is, each propeller-blade shank 29 extends radially inward through a respective opening 20, being rotatably journaled therein, toward the groove 25 of inner shaft 21. The shanks 29 may be of generally cylindrical configuration, each being provided on its inner end 30 with a castellated or toothed formation of teeth 31. The teeth 31 are arranged'in an arcuate array circumferentially about the inner end 30 of the respective shank 29, with the teeth projecting longitudinally of the shank inward therefrom for entry into the groove 25 and interfitting engagement with the teeth 26 of the inner shaft 21. Along the circumferential path of teeth 31 there may be formed an arcuate abutment segment or land 32 for abutment and limiting engagement with the inner-shaft teeth 26.

Rotatably retaining the shanks 29 in their respective openings 20 may be any suitable retainer means, such as pins 33 extending through the outer-shaft end enlarge ment into circumferential grooves 34 of respective shanks.

It will now be appreciated that upon axial rotation of the inner shaft 21 relative to the outer shaft 15, the interfitting engagement of inner-shaft teeth 26 with propeller-blade-shank teeth 31 effects axial rotation of the propeller blades in the journal openings 20 to a limiting position determined by engagement of the abutments 32 with the teeth 26. Continued rotation of inner shaft 21 effects simultaneous rotation of outer shaft 15 and rotation of the propeller blades 28 about the axis of the inner shaft. Upon reversed direction of rotation of drive shaft 23, the same action occurs and terminates with the propeller blades 28 in an opposite extreme limitin-g position, approximately 180 degrees away from the first-described limiting position.

Assuming the drive shaft 23 to be rotating in the direction of arrow 35 in FIGURE 1, wherein the axial rotation of shanks 29 has reached its limiting position, the propeller blades 28 will rotate in the same direction as shaft 21. This condition is shown in FIGURE 2, the propeller blade 28 moving in the direction of arrow 37 and its airfoil configuration properly arranged to effect maximum thrust for forward movement of the mounting structure 11. Upon reversal of rotation of drive shaft 23, the airfoil configuration of each blade 28 is rotated approximately 180 degrees to the condition of FIGURE 2a, and the direction of blade movement is there indicated by arrow 38. It will thus be apparent that the airfoil configuration is arranged for effective braking action upon reversal of drive shaft 23.

However, the above-described description of operation places a degree of reliance upon inertia forces which, under some conditions, may be unreliable. In order to assure positive pit-ch reversal of the blades 28, a clutch means, generally designated 40, is located for engagement with the outer shaft 15. In operation, as will appear more fully hereinafter, during reversal of direction of drive shaft 23, the clutch means 40 momentarily holds the outer shaft 15 against rotation with the inner shaft 21. This places the teeth 26 of the inner shaft 21 in direct driving engagement with the teeth 31 of the shanks 29 to positively effect axial rotation of the shanks to reverse their pitch.

More particularly, the clutch means 40 may include a brake wheel 41 circumposed about the outer shaft 15, and keyed thereto, as by a key 42. The outer peripheral surface 43 of the brake wheel 41 may provide a braking or drum surface. A brake belt 44 may be trained about the brake wheel 41, having one end connected, as by a loop 45 to a pivot 46 carried at one end of a lever or arm 48. The other end of brake belt 44 is pivoted, as by a pivot pin 50 to the lever 48, adjacent to and inward of the'pivot pin 46. Thus, it will be appreciated that upon downward or clockwise swinging movement of the lever 48, as seen in FIGURE 3, the belt 46 is tightened about the drum or wheel 41, to effect braking action on the drum, and consequently on the outer hollow shaft 15. The lever may carry a weight 51, adjustable along the lever, for proper operation, if desired.

Effecting operation of the clutch means 40 may be a solenoid 52 having a shiftable slug or rod 53 pivotally connected at one end, as by a pin 54 to the lever 48, spaced from the pivots 46 and 50. Thus, upon energization of the solenoid 52, as in the condition of FIGURE 3, the solenoid slug or rod 53 is shifted downwardly to swing the lever 48 and tighten the brake band 44 about the drum surface 43. Deactuation of solenoid 52 permits upward movement of lever 48 under spring action.

A diagrammatic electrical circuit is shown in FIG- URE 3, including a conductor 55 connected between one side of the coil of solenoid. .2 and o e Side of a battery or electric-power source 56. An operating lever is illustrated at 57, mounted on a pivot 58 for swinging movement between a forward position at 59 and a reverse position at 60. Upon movement between the forward and reverse positions, the lever 57 passes through a neutral position 61. A knife blade or movable contact 62 may be operatively connected by any suitable means to the lever 57 for movement in response to movement of the operating lever. The switch blade 62 is connected by a conductor 63 to the other side of electrical-power source or battery 56, and has interposed therein an onoff switch 64. An additional conductor 65 is connected between the other side of the coil of solenoid 52 and a contact 66 adapted to be engaged by the blade 62 upon swinging movement of the control arm 57 in the neutral position.

Thus, in operation, when the switch 64 is closed, actuation of control arm 57 between forward and reverse, in either direction, closes the blade 62 to engage contact 66, at least momentarily, to energize the solenoid 52 and effect operation of brake or clutch 40. It is this momentary holding of the outer shaft 15, as described hereinbefore, which effects positive axial rotation of the propeller shanks 29 to insure their pitch reversal upon direction reversal of shaft 35.

In FIGURE 4 is illustrated the normal operating condition of the control lever 57 in reverse, with the blade 62 out of engagement with contact 66, so that the solenoid 52 is not energized. The phantom position illustrating the control arm in forward position is similar.

From the foregoing it is seen that the present invention provides a changeable-pitch propeller which is extremely simple in construction, positively insures pitch reversal upon direction reversal of the drive means, and otherwise fully accomplishes its intended objects.

Although the present invention has been described in some detail by way of illustration an example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. A changeable-pitch propeller comprising an axially rotatable hollow outer shaft having a plurality of radially extending thru openings, an axially rotatable inner shaft extending coaxially within said outer shaft for rotation with and relative to said outer shaft, said inner shaft being adapted for connection to a reversible power shaft, a plurality of blade shanks journaled in said thru openings for rotation with said outer shaft and rotation relative thereto about the respective axes of said openings, a propeller blade projecting from each of said shanks generally radially of the outer shank, interengaging drive means on said inner shaft and on the inner ends of said shanks for axially rotating the latter in opposite directions upon axial rotation in opposite direc' tions of said inner shaft relative to said outer shaft, limit means limiting the axial rotation of said shanks to predetermined positions in opposite directions of innershaft rotation relative to said outer shaft, and clutch means engageable with said outer shaft upon direction reversal of said inner shaft to rotate said outer shaft relative to said inner shaft, whereby reversed rotation of said inner shaft effects axial rotation of said shanks to change the pitch of said blades.

2. A changeable-pitch propeller according to claim 1, said drive means comprising interfitting toothed formations carried by said inner shaft and shanks.

3. A changeable-pitch propeller according to claim 1, said clutch means comprising a brake engageable with said outer shaft, control means for changing direction of said inner shaft, and operating means connected between said control means and brake for momentarily engaging the latter upon actuation of said control means to reverse direction.

5 S 6 4. A changeable-pitch propeller according to claim 3, 1,946,387 2/1934 Chance et a1. 170160.29 X said operating means comprising electrical means opera- 2,504,737 4/1950 Sharpes 170-1601 tively connected between said control means and brake. 3,294,176 12/1966 Reimers 170-160.1

References Cited 5 FOREIGN PATENTS UNITED STATES PATENTS 984,485 2/1951 France. 1,719,953 7/1929 Wiegand 170-16029 X A. JR-, Primary Exam n r. 

1. A CHANGEABLE-PITCH PROPELLER COMPRISING AN AXIALLY ROTATABLE HOLLOW OUTER SHAFT HAVING A PLURALITY OF RADIALLY EXTENDING THRU OPENINGS, AN AXIALLY ROTATABLE INNER SHAFT EXTENDING COAXIALLY WITHIN SAID OUTER SHAFT FOR ROTATION WITH AND RELATIVE TO SAID OUTER SHAFT, SAID INNER SHAFT BEING ADAPTED FOR CONNECTION TO A REVERSIBLE POWER SHAFT, A PLURALITY OF BLADE SHANKS JOURNALED IN SAID THRU OPENINGS FOR ROTATION WITH SAID OUTER SHAFT AND ROTATION RELATIVE THERETO ABOUT THE RESPECTIVE AXES OF SAID OPENINGS, A PROPELLER BLADE PROJECTING FROM EACH OF SAID SHANKS GENERALLY RADIALLY OF THE OUTER SHANK, INTERENGAGING DRIVE MEANS ON SAID INNER SHAFT AND ON THE INNER ENDS OF SAID SHANKS FOR AXIALLY ROTATING THE LATTER IN OPPOSITE DIRECTIONS UPON AXIAL ROTATION IN OPPOSITE DIRECTIONS OF SAID INNER SHAFT RELATIVE TO SAID OUTER SHAFT, LIMIT MEANS LIMITING THE AXIAL ROTATION OF SAID SHANKS TO PREDETERMINED POSITIONS IN OPPOSITE DIRECTIONS OF INNERSHAFT ROTATION RELATIVE TO SAID OUTER SHAFT, AND CLUTCH MEANS ENGAGEABLE WITH SAID OUTER SHAFT UPON DIRECTION REVERSAL OF SAID INNER SHAFT TO ROTATE SAID OUTER SHAFT RELATIVE TO SAID INNER SHAFT, WHEREBY REVERSED ROTATION OF SAID INNER SHAFT EFFECTS AXIAL ROTATION OF SAID SHANKS TO CHANGE THE PITCH OF SAID BLADES. 